Avian Distribution Patterns and Conservation in Amazonia

by Vale, Mariana M

Abstract (Summary)

In this dissertation, I address the distribution and conservation of the Amazonian avifauna at several different scales. In Chapter 1, I looked at how the spatial bias in ornithological collections affects our understanding of the patterns of diversity in Amazonia. I showed that Amazonia is massively under-collected, that biological collection sites cluster around points of access, and that the richness at collection localities is higher than would be expected at random. This greater richness in collected areas was associated with a higher proportion of species with small geographical ranges as compared to uncollected areas. These small range species are relevant for conservation, as they are especially prone to extinction. I concluded that the richness of the uncollected areas of Amazonia is seriously underestimated, and that current knowledge gaps preclude accurate selection of areas for conservation in Amazonia. With this in mind, I modeled the impacts of continued deforestation on the Amazonian endemic avifauna. To overcome knowledge gaps, I complemented bird range maps with a "bird-ecoregions." I identified several taxa and bird-ecoregions likely to face great threat in the near future, most of them associated with riverine habitats. To evaluate these predictions, I conducted a detailed study on two riverine species: the Rio Branco Antbird (Cercomacra carbonaria) and the Hoary-throated Spinetail (Synallaxis kollari). Both are threatened and endemic to the gallery forests of Roraima, Brazil. I predicted that both would lose critical habitat in the near future. I concluded that neither is categorized correctly in by The World Conservation Union and recommend the down-listing of the Rio-Branco-Antbird and the up-listing of the Hoary-throated Spinetail. I also explored the importance of indigenous reserves for the conservation of both species and emphasized the need for greater involvement of conservation biologists in the social issues related to their study organisms.